This invention relates to a manually operated pump device for dispensing fluids from containers, particularly of the portable type for connection to said containers, for example by threaded ring nuts or capsules.
Fluid dispensing pumps are known, consisting substantially of a trigger lever, a delivery channel and a handgrip containing in its interior a pumping system formed from a cylinder-piston assembly operationally connected to the lever, suction and delivery valves, and elastic return means.
The unidirectional valves provided in known pumps consist of shutoff valves of conventional type, for example of gravity or spring-loaded type.
Known pumps with a gravity valve on the delivery side operate properly only if used vertically or slightly inclined to their axis, otherwise the necessary force for their closure is not available. This is not the case with spring-loaded valves. However these latter also have drawbacks, in that during the suction stage, as the elastic force of the spring also has to be overcome a greater pressure difference is required between the pumping chamber and the container, which makes it very difficult to draw in dense liquids. In any event the use of springs increases the number of pump components and complicates their shape and assembly.
In addition, conventional pumps cannot be used with resinous or gluey liquids, in that if they dry in the pumping part they permanently block the pump.
Known pumps also generally drip annoyingly from the orifice of the delivery channel after operation.
Again in known pumps, it is not usual to provide a delivery head which enables the fluid to be delivered in different forms, for example in jet, spray, foam or atomized form.